The higher order wave equation of KdV type, which describes many important physical phenomena, has been investigated widely in last several decades. In this work, multisymplectic formulations for the higher order wave equation of KdV type are presented, and the local conservation laws are shown to correspond to certain well-known Hamiltonian functionals. The multi-symplectic discretization of e...

In [BMV03]and [Bre02] the authors proposed to compute the characteristic roots of Delay Differential Equations (DDEs) with multiple discrete and distributed delays by approximating the derivative in the infinitesimal generator of the solution operator semigroup by Runge-Kutta (RK) and Linear Multistep (LMS) methods, respectively. In this work the same approach is proposed in a new version based...

An orthogonal system of rational functions is introduced. Some results on rational approximations based on various orthogonal projections and interpolations are established. These results form the mathematical foundation of the related spectral method and pseudospectral method for solving differential equations on the half line. The error estimates of the rational spectral method and rational p...

We extend the application of Legendre-Galerkin algorithms for sixth-order elliptic problems with constant coefficients to sixth-order elliptic equations with variable polynomial coefficients. The complexities of the algorithm are O(N) operations for a one-dimensional domain with N − 5 unknowns. An efficient and accurate direct solution for algorithms based on the LegendreGalerkin approximations...

The problem of performance optimization of a maneuvering re-entry vehicle is studied. The objective is to determine an optimal steering law for a high lift-to-drag ratio vehicle. An optimization criteria is derived that attempts to maximize the control margin of the vehicle in order to account for unmodeled perturbations during actual flight. The optimization problem is formulated as an optimal...

Non-invasive, focal neurostimulation with ultrasound is a potentially powerful neuroscientific tool that requires effective transcranial focusing of ultrasound to develop. Time-reversal (TR) focusing using numerical simulations of transcranial ultrasound propagation can correct for the effect of the skull, but relies on accurate simulations. Here, focusing requirements for ultrasonic neurostimu...

Seismic modeling is a foundation of geophysical date processing. A multisymplectic pseudospectral method for seismic modeling is presented in this paper. This method takes the multisymplectic structure of the scalar wave equation into account and possesses discrete multisymplectic conservation laws. Numerical experiments demonstrate the remarkable capability of this new method for long-time sim...